INTRODUCTION Students in chemistry class learn that chemistry helps them recognize how the differences in the properties of matter relate to what the matter is composed of Jon Feingersh Blend Images Getty Images
INTRODUCTION hy do onions make people cry What makes fireworks explode How do rechargeable batteries recharge All these questions and many more can be answered with one simple word chemistry Chemistry plays a very large role in everyday life Without it bread would not rise cleaners would not clean and life itself would not exist Chemistry is the study of matter and the changes that matter undergoes Anything you can see touch smell or taste is made up of matter An airplane is matter An ant is matter The air that surrounds you is made up of matter too although you cannot see it Matter is anything that has mass and occupies space Sound and light though are not matter Unlike air they do not have mass or take up space A pure substance is matter that has a spe cific composition and definite properties Elements and compounds are pure sub stances but mixtures such as apple juice are not Apple juice is a mixture of many pure substances such as water sugars and vitamins The chapters in this book introduce the major concepts of the phys ical and chemical properties of
CHEMISTRY UNDERSTANDING SUBSTANCE AND MATTER including characteristic properties the use of chemical analysis and the physical and chemi cal changes that occur on the molecular level You will also investigate the classification of matter according to its chemical composition by element compound and mixture All matter consists of very small build ing blocks called atoms Chemists study how atoms interact with one another These inter actions affect everything they cause plants to grow fireflies to glow and bread dough to rise They govern how the food you eat is turned into energy and they are the reason that the leaves on some trees change color in the fall Why should you study chemistry People in many professions including medicine envi ronmental science and marine biology need a good working knowledge of chemistry But they are not the only ones Chemistry is very important in today's society To be an informed consumer you need to know what goes into the food you eat the beverages you drink and the clothes you wear Do you know how much fertilizer is needed to make your lawn green and how much is too much Do you know which household chemicals are safe to com bine and which are not Studying chemistry can help you answer these questions and many 10
INTRODUCTION others For this reason everyone could ben efit from knowing a little bit about chemistry and its underlying concepts Over time scientific knowledge builds on itself and the study of chemistry is no excep tion The discovery of the atom and the investigation of how atoms interact with one another have changed the world Chemists today strive to make the world a better place by studying new materials that can make life easier protect the environment and provide energy that humans can use In this volume you will be treated to an overview of the history and concepts you may encounter in an introductory chemis try course People use chemicals every day when they cook clean or take medications Chemical reactions happen all around you as you breathe eat or sit to read As your under standing of chemistry grows you will see that chemistry helps explain the world you live in and to varying degrees we are all chemists 11
